Method and apparatus for forming sheet-glass



Dec; 17 1929. I H. ELALLEN; ET AL I 3 ,9

' METHOD AND APPARATUS FORFORMING SHEET GLASS File d Feb '1} 1928"Horace E. fi/len Ld l lbur Drown Patented Dec. 17, 1929' UNITED srArEs,PATENT OFFICE HORACE E. ALLEN Am) wimaun r. renown, or 'rornno, or'rro,ssrsnons ,TO ILIBIBEY: ownns GLASS COMPANY, OF TOLEDO, OHIO, ACORPORATION or OHIO mn'rnon AND ArrAnAr s ron FORMING snnn'r- GLAssApplication filed rebmar 1;.-i92s. Seria1 No.'251,031.

The Pr sent} invention relatesto sheet drawingvapparatus and hasparticular reference to that type of machine wherein the sheet of glassis drawn through a slot formed in a suitable member, the said memberbeing disposed in a source of moltenglass.

One of the primary objects of this'invention is to provide means foreliminating or reduc ing defects on thesurface of the glass. 1

prove the character of the surface of the glass sheet being drawn.

Still another object of this invention is to provide sheet. glassdrawing apparatusemploying a deputer so constructed and manip ulatedthat a meniscus is' provided, the molten glass therefor being suppliedby three sep-" arate streams. Another object of the invention is toprovide means wherein the glass forming the. outer surface of the drawnsheet is furnished by a surface flow of glass-to the meniscus wherebythe formed sheet i: be free of the so-called water silk lines 'or' othersurface defects. f

Still another object ofthe invention is to provide sheet drawing meansof this character employing a deputer so constructed and manipulatedthat a meniscus is formed by the combined flow of two streams of moltenglass downwardly from opposite directions together with an upwardlyflowing stream flowing under ahydrostatic head.

Still another object of the mvention is to provide a .deputer of thischaracter wherein the shelves of the deputer are covered with a materialformed of a non-corrosive alloy whereby the solvent action of the glasson the shelves with respect to the meniscus, is eliminated; v p

Various other objects, advantages and novel details of construction ofthis invention will be made more apparent as this description proceeds,especially when considered in. 1 connection with'the accompanyingdrawings wherein: t

Figure 1 is a fragmentary vertical longi tu'dinal sectional view througha sheet drawing apparatus constructed in accordance with this invention.

Figure '2 is afragmentarytransverse ver tical sectional View through thestructure illustrated in Figure 1.

. Figure 3 is an enlarged vertical-sectional view through the deputer.

--Figure 4 is a similar VleW of a slightly modified form of constructionand Figureo is a' similar view of still anothera v modified formbfconstruction. Another object of the invention is to im-' Referring nowto the drawings and more particularly to Figure 1thereof'it'will be 7 anoted that there. isillustrated a draw pot or instance, by nfeans of acontinuous tank furmice 12. In accordance with the type of maf chineherein disclosed thesheet of glass 13 is drawn vertically from the drawpot 10 and passesbetween rollers'l l. In order to permit acontlnuousdrawing of glass from the pot 10 a member 15,-which is knownin the art as a de'puter, is submerged in the molten glass lland .isprovided with a longitudinal slot 16 through which the glass sheet 13 isdrawn. Ordinarily the deputer' 15' is formed of a refractory, material,which has a tendency to create a'drag on the sheet being drawn due tothe tendency of the glass to adhere to such mate rial. In this manner asheet of glass can 'be continuously drawn from a source of molten glass.

. An object of the invention is to eliminate the possibility of linesand other surface defects being formed in the sheet as it passesupwardly from'the slot 16 of the deputer. In order to accomplish this wepropose submerging the deputer so that a surface flow of 1 glass to themeniscus will occur. In order to obtain these results we propose forminga lon 'itudinally extending recess 17 in the top sur ace of the deputer,the longitudinal side walls 18 thereof being inclined downwardly topoints adjacent the slot 16. It will be noted that the slot 16 opensinto the longi- Any desired or preferred means maybe i employedformounting and adjustably'suptudinally extendingrecess 17 and that theporting the deputer but in the form of construction herein illustratedthe deputeris shown as provided -with extens1ons or arms '20 at the endsthereof provided with adjusting means 21 engaging the wall of thedrawpot or some other suitable support. By prop-. erlyadjusting themeans 21 the deputer'can be raised and lowered as desired. y

In practice it is proposedto submerge the deputer in themolten glass 11sufiiciently to bring its" upper surface 19 slightly below the 'level ofthe moltenglass 11 'In this manner two streams of molten glass 22 arecreated and caused to flow by gravity downwardly over the downwardlyinclined faces -18 of therecess l7 and to unite at a point substantiallycoincident with theslot l6 and to co-operate-to produce the meniscus'23.

At the same time a stream'24 of molten glass is caused to flow upwardlythrough s1ots16 by reason of hydrostatic head pressure of the puter sothat the glass forming the'outer sur face of the drawn sheet does notcome in contact with the deputer and as a consequence will be free fromlines or other surface defects.

a surface of glass produced in the manner here- It is believedthat theso called water silk lines, which 'are frequently present on the indescribed5 result from the solvent action of the small amount of glasswhich accumulates and is present on the shelves of thedeputer from whichthe meniscus rises. This glass usually contains a relatively largeamount of alumina'and we propose preventngsuch an accumulation of thisglass relatively high in alumina whereby to prevent the formation ofthese water silk lines in the final sheet. In this connection referencepreviously described one.

is made to Figure 4 wherein the deputer 25 which is' substantiallyidentical in constr.uc-

tion with the previously described deputer 15 is'pr'ovided with members26 formed preferably of some non-corrosive alloy, these members beingarranged to fit and cover the shelves of the deputer. In other respectsthis construction of deputer functions as does the In Figure 5the'd'eputer27 is provided with a slot 28 extending upwardly and openinginto the bottom of a relatively shallow recess 29. In this form ofconstruction the deputer will be submerged below the level of moltenglass 11, whereby molten glass will fillthe relatively shallowrecess 29,a stream of molten glass being forced up through slot '28 by reason ofhydrostatic head or pressure ofthe molten glass 11. The presentconstruction and method of operation differs from those previouslydescribed in thatthe deputer is submerged sufi'i'ciently far to have themeniscus 30 start on the level of the glassin the draw pot-.5 However,as in the previously described form, the molten glass fiowing intotheouterssurface of the sheet 13.

does not come in'-:c;ontact with the deputer.

Obvious modifications of the presentv invention will suggest themselvesto others skilled in this art and to this end reservation is made tomake such changes in many of the essential and all of thenon-esjsenti'al details of construction andmethod of operation as maycome within the-purview of the accompanying claims. I

VVeclaimt 1. In the method offorming sheet glass, those steps whichconsist informing a meniscus-by a combined flow of glass downwardlyfrom'opposite (directions and a hydrostaticfiow. y

2. In the method of form-ingsheet glass;

those steps which consistin creating tW streams of molten glass bygravity flow and creating a stream by hydrostatic pressure,-

which streams unite to form the meniscus'of the sheet. I v V I 3. In themethod of forming sheet glass, v those steps which consist in creatinga'hy'clroof these streams.

4. In the method .of formingsheetjglass niscus by flowing streams ofmolten glass those steps which'consistin creatinga mehead through thecenter of the deputer, as and for the purpose set forth.

static flow and a surface flowof molten glass and drawing a sheet ofglass from the union 6 The method of forming sheet glass whichcomprises, flowing streams of molten glass downwardly in oppositedirections in contact with a deputer and flowing a stream of moltenglass upwardly under a hydrostatic head through the center of thedeputer and drawing a sheet of glass from the united streams. I i

7. The method of forming sheet glass which comprises, flowing streams ofsurface molten glass downwardly from opposite directionsin contact witha deputer and fiowin'g astream of molten glass upwardly under ahydrostatic head through the center of the deputer, uniting the streamsand drawing asheet of glass from the united streams whereby the surfaceglass sheet.

8; In the method of forming sheet glass,

forms the surface of the those steps which consist in creating twostreams of molten glass by gravity flow, maintaining one surface of saidstreams free from contact, creating a stream by a hydrostatic head anddrawing a sheet from the union of said streams.

9. In the method offorming sheet glass, those steps which consist increating two streams of molten glass by gravity flow, maintaining onesurface of said streams free from contact, creating-a stream bya'hy'clrostatic' head, uniting the streams to create a meniscus fromwhich a sheet of glass is drawn, the surfaces of the streams which weremaintained free from contact forming the surfaces of the drawn sheet.

10. In the method of forming sheet glass, those steps which consist increating two streams of molten glass'by gravity flow, maintaining onesurface of said streams free from contact, creating a stream by ahydrostatic head, uniting the streams and drawing a continuous sheet ofglass therefrom, the uncontacted surfaces of the said gravity flowedstreams constituting the surfaces of the formed sheet.

11. The combination with sheet glass drawing apparatus, of a deputerprovided with a slot through which a stream of glass is flowed byhydrostatic pressure and means whereby surface glass may be flowed anddirected to" unite with said first stream to form a meniscus from whichthe sheet is drawn. Y

12. The combination with sheet glass drawing apparatus, of a deputerprovided with a longitudinal vertically extending slot, a recess formedin the upper facepf said deputer, said slot opening into the bottom ofsaidrecess and means for submerging said deputer into a mass of moltenglass whereby a stream of glass under hydrostatic pressure will'flowthrough said slot and surface glass will be directed by said recesstoward said first stream and united therewith to form a source fromwhich a sheet of glass may be continuously drawn.

Signed at Toledo, in the county of Lucas, and State of Ohio, this 30thday of January,

HORACE E. ALLEN. WILBUR r; snows.

